Sewage chopper pump



L. L. NELsEN July 22, 1969 SEWAGE CHOPPER PUMP 2 Sheets-Sheet l FiledMarch 4, 1968 mm. m

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Nl L Mw w L y July 22, 1969 L. l.. NELSEN SEWAGE CHOPPR PUMP 2Sheets-Sheet 2 Filed March 4, 1968 0 2 ///7/\/^/H\ 8 4 8 0|'. 3 5 5 n 6M5 5 HHM 1E MN. w l 2m 2f m l w 8\ M 2 60 o m v 6 37 M. :if F 4 2\ 8Lloyd L. Ne/sen INVENTOR.

United States Patent O M 3,456,592 SEWAGE CHPPER PUMP Lloyd L. Nelsen,Parma, Idaho, assignor to Parma Water Lifter Company, a corporation ofIdaho Filed Mar. 4, 1968, Ser. No. 710,314 Int. Cl. F04d 1/14; B02c21/00, 18/10 U.S. Cl. 103-111 10 Claims ABSTRACT F THE DISCLGSURE Acombination centrifugal pump and cutter assembly for removing liquidslurries from an underground well. Cutter blades having spiral cuttingedges cooperate with shear bars to chop pump clogging solids above thetop axial inlet to the pump. The cutter blades are fastened to the driveshaft above the pump inlet and are vertically adjustable therewithrelative to the shear bars from an above surface location on a mountingplatform 'below which the drive shaft extends within a tubular casing.

This invention relates to nonclogging types of centrifugal pumpsparticularly adapted to the vertical displacement of solid contaminatedliquids such as sewage.

In submerged pump installations with which the present invention isconcerned, eflicient and rapid displacement of liquid requires the topmounting of the axial inlet for the pump about the vertical impellerdrive shaft. However, a clogging problem presents itself since gravityenhanced concentrations of solids will enter the pump inlet and tend toclog the pump.

In an attempt to alleviate this problem, it has been proposed in PatentNo. 2,714,354 to Farrand that horizontal rotary cutter blades be mountedon the vertical impeller drive shaft closely spaced above the intakeopening in the pump housing with the blades extending radially beyondthis intake opening by a substantial amount so as to chop or -comminutesolids. Such an arrangement is not entirely satisfactory since ltherotary cutter blades are not completely effective to prevent entry ofpump clogging solids into the pump housing through the intake openingand do not prevent the concentration of solids adjacent the intakeopening. Thus, the rotary cutter blades may even contribute to theoverloading of the impeller drive shaft.

The foregoing inadequacy of the prior art in overcoming the pumpclogging problem, is effectively eliminated by the arrangement of thepresent invention to provide a trouble-free, nonclogging submerged pumpinstallation which may also be externally adjusted so as to maintaineffective chopping action to prevent clogging of the pump.

In accordance with the present invention, a centrifugal pump unitsuspended by a tubular casing through which the pump impeller driveshaft extends mounts a chopper blade assembly within the spiderconnecting the lower end of the tubular casing to the pump housing aboutthe pump intake opening. The chopper assembly includes cutter bladeswhich extend vertically a substantial distance between the spiderassembly and the pump housing having radially outer, spiral cuttingedges closely spaced inwardly from the outer periphery of the intakeopening and cooperating with closely spaced, stationary shear barsmounted on posts which vertically space the spider assembly from thepump housing and interconnect the same with the pump housing. Ro-tationof the drive shaft with which the cutter blades rotate, is effective tocause axial upward displacement of pump clogging solids by the cutterblades, as the cutting edges shear and comminute the solids bycooperation with the shear bars. Thus, the chopper assembly preventsconcentration of 3,456,592 Patented July 22, 1969 clogging solids in thevicinity of the pump intake opening to reduce loading of the chopperblades without any substantial impedance to the flow of noncloggingmaterial into the intake opening. Furthermore, shearing of solidsbetween the spiral cutting edges of the chopper blades and the shearbars occ-urs closely spaced radially inwardly of the intake openingperiphery so that comminuted material may directly ow into the intakeopening.

The radial distance of the spiral cutting edges and the cooperatingshear bar surfaces vary in an axial direction, increasing downwardly bya small amount. Thus, when the spacing between the cutting edges and theshear bar surfaces increases because of wear, the cutter blades may beaxially adjusted upwardly through the drive shaft in order to restorethe proper spacing and thereby maintain the effectiveness of the chopperblade assembly. Such adjustment may be effected at the upper end of thedrive shaft above the platform frame from which the pump assembly issuspended.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE l is a side section view showing the apparatus of the presentinvention in side elevation, in a typical installation.

FIGURE 2 is an enlarged top section view taken substantially through aplane indicated by section line 2-2 in FIGURE 1.

FIGURE 3 is an enlarged side sectional view taken substantially througha plane indicated by section line 3-3 in FIGURE 1.

FIGURE 4 is an enlarged partial sectional view taken substantiallythrough a plane indicated by section line 4-4 in FIGURE 2.

FIGURE 5 is a top sectional view taken substantially through a planeindicated by section line 5 5 in FIG- URE 4.

FIGURE 6 is an enlarged partial sectional View taken substantiallythrough a plane indicated by section line 6-6 in FIGURE 4.

FIGURE 7 is a perspective View of one of the shear bars associated withthe apparatus of the present invention.

Referring now to the drawings in detail, FIGURE 1 illustrates theapparatus of the present invention generally denoted by referencenumeral 10 adapted to be installed at a location for displacing a liquidslurry from a deep underground well or sump 12. The apparatus includesan above surface frame assembly 14 including a platform portion 16overlying the sump from which a centrifugal pump device 18 is suspendedby means of a tubular casing 20 interconnected with the pump devicethrough a chopper assembly generally referred to by reference numeral22. The pump device 18 when operated causes displacement of liquid fromthe body of liquid 24 within which it is submerged upwardly through anassembly of vertical discharge conduits 24 to an above surface location.The pump device is driven by means of an elongated impeller drive shaft26 extending through the tubular casing 20 between the pump device 18and a multisheaved pulley wheel 28 above the platform 16. The pulley 28is connected by the endless drive belts 30 to a multisheaved drivepulley connected to the output shaft of an electric motor 32 secured tothe frame assembly 14 and constituting the prime mover.

As more clearly seen in FIGURES 2 and 4, the centrifugal pump deviceincludes a lower housing section 34 bolted to an upper housing section36. The housing sections form a tangential outlet 38 connected by thetransition conduit sections 40 to the assembly of vertical dischargeconduits 24 aforementioned. The central opening 42 in the lower housingsection 34 is closed by a plate 44 bolted to the housing section andmounting a thrust bearing assembly 46 receiving the lower end of thedrive shaft 26 which may be formed from two or more shaft sectionsinterconnected by internally threaded couplings 48. The drive shafttherefore extends into the pump housing through an intake opening 50formed in the upper housing section 36. The housing sections enclose aplurality of radially extending impeller blades 52 having a hub portion53 which is splined to the drive shaft 26. Rotation of the drive shaftby means of the motor 32 will therefore transmit rotation to theimpeller blades causing tangential discharge of liquid entering thehousing through the intake opening 50 from the tangential outlet 38.

The tubular casing 20 through which the drive shaft extends, includestwo or more tubular sections 54. Adjacent ends of the tubular sections'4 are spaced apart by collar members 56 as shown in FIGURE 4 throughwhich the drive shaft 26 extends and maintained in concentric relationto the tubular casing assembly. A coupling collar 58 threadedly engagesthe externally threaded adjacent end portions of the tubular sections 54to make a liquid tight assembly. The upper externally threaded end ofthe uppermost tubular casing section 54 is threadedly received withinthe internally threaded lower end portion of a bearing member 60 havinga mounting ange 62 secured by a plurality of fastener bolt assemblies 64to the platform 16. Spaced bearings 66 and 68 as shown in FIGURE 3, aresupported on axially spaced thrust shoulders internally formed withinthe bearing member 60 in order to rotatably support a mounting sleeve 70connected to the pulley 28 and the drive shaft 26 above the bearingmember by means of the spline 72. The drive shaft is held in avertically adjusted position relative to the sleeve 70 by means of anadjustment collar 74 threadedly engaging an upper threaded end portion76 of the drive shaft to which the collar may be locked by means of thesetscrew 78. It will be appreciated therefore, that the verticalposition of the drive shaft assembly may be adjusted either upwardly ordownwardly by loosening the setscrew 78 and axially advancing theadjustment collar 74 upwardly or downwardly. The lower end of the driveshaft on the other hand is slidably connected to the impeller blades asaforementioned so that it may be axially displaced relative thereto andrelative to the tubular casing assembly from which the pump device 18 issuspended.

The lower end of the tubular casing assembly is connected to the hubportion 80 of a spider assembly having four spider arms 82 in theillustrated embodiment extending radially outwardly from the hubportion. The spider arms are secured by the fasteners 84 to a plate 86having a central opening through which the drive shaft 26 extends. Thespider assembly is vertically spaced by a substantial distance from theupper housing section by means of three posts 88 welded to an annularframe 90 having cutout openings 92 between the posts as more clearlyseen in FIGURES 5 and 6. The annular frame 90 includes a top portion 94to which the spider arms 82 and plate 86 are secured by the fasteners 84and through which the drive shaft 26 extends. Tabs 96 extend radiallyoutwardly from the annular frame 90 at its lower end in alignment withthe posts 88 for securing the frame to the upper section 36 of the pumphousing by means of the fasteners 98. The posts 88 are therebypositioned by the annular frame 90 in equal circumferentially spacedrelation to each other on the upper housing section right at theperiphery 100' of the intake opening 50. Each of the posts 88 isaccordingly adapted to mount a shear bar 102 in proper position relativeto the intake opening 50.

As more clearly seen in FIGURES 4, 6 and 7, each of the shear barsincludes a leg portion 104 secured by a plurality of fasteners 106 toone side of a post S8. Fastener receiving apertures 108 are accordinglyformed in the leg 104. The other leg portion of the shear bar restsagainst the side of post 88 positioned on the periphery 100 of theintake opening so as to be disposed on the inside of the intake openingat the periphery presenting an arcuate surface 110 closely spacedradially inwardly from the periphery of the intake opening. The arcuatesurface has a center of curvature which lies on the rotational axis ofthe drive shaft 26. Furthermore, the thickness of the leg portion of theshear bar presenting the arcuate Surface 110 varies from a maximum atits upper end to a minimum at its lower end as shown in FIGURE 4.Accordingly, there is a slight increase in the radial distance of thearcuate surface 110 in a downward direction. This radial variationcorresponds to a similar radial variation in the dimensions of thecutter blades 112 mounted on and projecting radially from the driveshaft 26.

The cutter blades 112 are equal in number to the shear bars 102 withwhich they cooperate to comminute solids. The cutter blades areinterconnected by a central hub 114 secured in any suitable fashion asfor example by the setscrew 116 to the drive shaft. The cutter bladesare furthermore secured by the hub 114 to the drive shaft in angularpositions aligned above the irnpeller blades 52 as more clearly seen inFIGURE 5. Each of the cutter blades is provided with a radially outercutting edge 118 closely spaced by a constant amount from the arcuatesurfaces 110 of the shear bars. The cutting edges accordingly vary inradial distance from the rotational axis of the drive shaft inaccordance with the dimensional variation aforementioned in connectionwith the arcuate surfaces 110 relative to the rotational axis.Furthermore, the cutting edges 118 of the cutter blades are spiralshaped. By virtue of this spiral shape, solids are progressively shearedbetween the cutting edges and the arcuate surfaces 110 of the shear barsin response to rotation of the drive shaft. Also, rotation of the cutterblades tends to axially displace solids upwardly away from the intakeopening 50 to thereby prevent concentration of solids and excessiveloading of the drive shaft at the chopper assembly.

It will be appreciated, that the cutting action of the chopper assembly22 will be most eiiicient for a given Spacing between the radially outercutting edges 118 of the cutter blades 112 and the shear bars 102. Thisspacing may change because of wear. Therefore, in order to maintainmaximum eiciency of the chopper assembly, optimum spacing between thecutter blades and the shear bars should be restored. This may be readilyeffected by vertical upward adjustment of the drive shaft 26 to whichthe cutter blades 112 are axially as well as rotationally secured. Thevertical adjustment may be effected through the adjustment collar 74 ashereinbefore described.

The foregoing is considered as illustrative only of the prinicples ofthe invention. Further, since numerous modications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In combination with a centrifugal pump submerged within a body ofliquid contaminated with pump clogging solids having a housing providedwith an axial intake opening, impeller blades and a vertically elongateddrive shaft connected to the impeller blades and extending upwardlytherefrom through the intake opening, means submerged within the body ofliquid for preventing clogging of the pump comprising a spider assemblythrough which the drive shaft extends vertically spaced above the pumpinlet, a plurality of shear bars xedly connected between the spiderassembly and the housing of the pump and cutter blade means connected tothe drive shaft between the spider assembly and the pump housing andhaving a spiral shape tending to upwardly displace the solids inresponse to rotation of the drive shaft, said cutter blade means havingat least one radially outer cutting edge cooperating with the shear barsto comminute the solids approaching the intake opening through thespider assembly.

2. The combination of claim 1 wherein said cutter blade means has atleast one radially outer cutting edge axially inclined to said shearbars and means for vertically adjusting the position of the drive shaftto vary the spacing between the cutting edge and the shear bars.

3. The combination of claim 2 including a mounting frame, a thrustbearing assembly mounted by the frame through which the drive shaftextends and a tubular casing interconnecting the spider and bearingassemblies in vertically Aspaced relation to each other, said driveshaft adjusting means being mounted above the thrust bearing assembly.

4. The combination of claim 3 including a plurality of posts xedlyspacing the spider assembly from the pump housing radially outwardly ofthe pump intake opening, and means securing the shear bars to the postsradially spaced from the drive shaft by an increasing amount in adownward direction and by a constant amount from the cutting edge.

5. The combintion of claim 4 wherein the cutter blade means is mountedon the drive shaft in alignment with the impeller blades, said cuttingedge being spiral shaped.

6. The combination of claim 5 wherein each of said shear bars includes avertically elongated portion having an arcuate surface confronting thespiral cutting edge closely spaced radially inwardly of the periphery ofthe pump intake opening.

7. The combination of claim 1 including a plurality of posts fixedlyspacing the spider assembly from the pump housing radially outwardly ofthe pump intake opening, and means securing the shear bars to the postsradially spaced from the drive shaft by an increasing amount in adownward direction and by a constant amount from the cutting edge.

8. The combination of claim 7 wherein each of said shear bears includesa vertically elongated portion having an arcuate surface confronting thecutting edge closely spaced radially inwardly of the periphery of thepump intake opening.

9. The combination of claim 1 wherein the cutter blade means is mountedon the drive shaft in alignment with the impeller blades, said cuttingedge being spiral shaped.

10. The combination of claim 9 wherein each of said shear bars includesa vertically elongated portion having an arcuate surface confronting thespiral cutting edge closely spaced `radially inwardly of the peripheryof the pump intake opening.

References Cited UNITED STATES PATENTS 942,297 12/1909 Van Ness 103--1022,027,015 1/ 1936 Bell 241-255 2,371,681 3/1945 Durdin 10S- 111.12,714,354 8/1955 Farrand ID3-111.1 2,975,714 3/1961 Nechine 10B-111.13,155,046 11/1964 Vaughan 103-111.1

FOREIGN PATENTS I960,112 10/1949` France.

HENRY F. RADUAZO, Primary Examiner U.S. Cl. X.R.

